[src/trunk]: src/sys/uvm Make uvmspace_exec() deal with procs that have no vm...

[martin <martin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/1ca84bd732ad
branches:  trunk
changeset: 767796:1ca84bd732ad
user:      martin <martin%NetBSD.org@localhost>
date:      Sat Jul 30 20:05:46 2011 +0000

description:
Make uvmspace_exec() deal with procs that have no vmspace (yet) at all.
Greatly simplifies the upcoming posix_spawn implementation.

diffstat:

 sys/uvm/uvm_map.c |  17 ++++++++++++++---
 1 files changed, 14 insertions(+), 3 deletions(-)

diffs (44 lines):

diff -r c02bd00e3568 -r 1ca84bd732ad sys/uvm/uvm_map.c
--- a/sys/uvm/uvm_map.c Sat Jul 30 20:05:36 2011 +0000
+++ b/sys/uvm/uvm_map.c Sat Jul 30 20:05:46 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_map.c,v 1.301 2011/07/30 19:29:12 martin Exp $     */
+/*     $NetBSD: uvm_map.c,v 1.302 2011/07/30 20:05:46 martin Exp $     */
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.301 2011/07/30 19:29:12 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.302 2011/07/30 20:05:46 martin Exp $");
 
 #include "opt_ddb.h"
 #include "opt_uvmhist.h"
@@ -4184,13 +4184,24 @@
 {
        struct proc *p = l->l_proc;
        struct vmspace *nvm, *ovm = p->p_vmspace;
-       struct vm_map *map = &ovm->vm_map;
+       struct vm_map *map;
 
 #ifdef __HAVE_CPU_VMSPACE_EXEC
        cpu_vmspace_exec(l, start, end);
 #endif
 
        /*
+        * Special case: no vmspace yet (see posix_spawn) -
+        * no races possible in this case.
+        */
+       if (ovm == NULL) {
+               p->p_vmspace = uvmspace_alloc(start, end);
+               pmap_activate(l);
+               return;
+       }
+
+       map = &ovm->vm_map;
+       /*
         * see if more than one process is using this vmspace...
         */